1. Field of the Invention
This invention relates to a remote register reading system and more particularly to a remote register reading system wherein data representing a meter reading is transmitted over a UHF FM data signal link or a communication line to a mobile or central interrogation station from a register remotely located from the interrogating point, and wherein interrogating signals from the central or mobile interrogating point are transmitted over a UHF AM communication link to the remotely located register meter reading station.
2. Description of the Prior Art
U.S. Pat. No. 3,705,385 issued Dec. 5, 1972 and incorporated herein by reference, describes in greater detail a prior art remote meter reading system of which this invention is an improvement thereof. Basically, in order to measure the amount of a commodity such as gas, electricity, water and the like consumed by a customer of a utility company, meters are provided which include a register for recording the amount of the commodity used. These meter registers are periodically read by employees of the utility company who must go generally on foot to each meter location to read the meter registers. It can readily be appreciated that such a procedure entails a great deal of expense since there are many meters to be read which require many employees. It is desirable therefore to read these meters remotely either from a mobile station or a central station. One such system utilizes remote meter registers located in a more accessible central reading station, with each of these registers connected to the remotely located meter registers. In some systems the central collecting station is utilized to transmit the meter reading upon interrogation or automatically to a mobile station or to another larger central information gathering station. In some systems automation of meter readings has been attempted by providing means for reading of the meter from a remote central location by way of a communication line such as the telephone line of the customer. Yet, another system, hereinbefore referenced, provides a transponder at the location of each meter which is to be read, to transmit the reading of the meter at which the transponder is located to a remotely located mobile or central station upon command from the remotely located mobile interrogating station. In such a system RF AM radio signals are utilized to transmit and receive control and data signals. In such a system it is necessary that the transmit/receive operations be carried out at separate frequencies of sufficient separation that they do not interfere with each other. A high stability crystal oscillator is employed at the interrogating station in order to maintain good frequency and spectrum control for the system. Another solution is to use a free running LC oscillator which although more economical than the crystal oscillator has a drift characteristics such that tuning of the receiver at the opposite end is very difficult.
What is needed is an improved system similar to the Batz U.S. Pat. No. 3,705,385 which is economical to produce and install, does not corrode or deteriorate when exposed to the atmospheric elements, and exchanges information between the remote meter station and the mobile interrogating station in a non-interfering manner.